* including tender green leaves, thinly sliced or coarsely chopped Bits of pungent green onion offset the richness of the potato. Rinse potatoes in cold water, then squeeze out excess liquid. Place potatoes in a mixing bowl with green onions, eggs, matzo meal, salt and pepper. Mix well. Heat about 1/8 to 1/4 inch oil in heavy frying pan, then drop spoonfuls of the batter into the hot oil. Fry several pancakes at a time, cooking until golden on the first side, then turning and cooking the other side. Serve immediately, accompanied by sour cream. Variation: Instead of green onions, add 1/2 to 2/3 cup chopped chives. PER SERVING (using a total of 2 tablespoons oil): 260 calories, 8 g protein, 37 g carbohydrate, 10 g fat (2 g saturated), 105 mg cholesterol, 44 mg sodium, 1 g fiber. Marlena Spieler writing in the San Francisco Chronicle, 12/16/92.